That’s what Chinese protesters earlier this week had to say outside Industrial and Commerce Bank of China offices in Guangzhou and Shanghai.

The protesters weren’t displaced farmers or migrant workers: Instead, they were a group of furious investors demanding that the country’s biggest bank bail out a trust company that had failed to pay its bills.

The protest took place on Monday, after investors learned that a trust product they had bought three years ago wouldn’t be paid out on time.

To date, a widely anticipated wave of defaults in China’s trust industry — a pillar of the country’s fast-growing shadow bank sector – has so far failed to materialize. But as this week’s protest indicates, the sector still shows signs of trouble.

The product, which was issued by China Credit Trust Co. and sold by ICBC, was backed by coal-mining assets and netted total investments of 1.3 billion yuan ($210 million). Originally, the product was set to mature late last month. However, on July 24 — the day before it was set to mature — the company said it would sell its collateral and pay back investors over the coming 15 months, instead.

Such an arrangement failed to appease the investors, each of whom invested at least 3 million yuan into the high-yield product, which promised around 10% annualized return.

“ICBC managers told us the product was safe and both the principal and interests are guaranteed,” said Zhang Liang, an investor from Guangzhou who attended Monday’s protest, which attracted roughly a combined several dozen participants in Shanghai and Guangzhou.

“If it wasn’t sold by ICBC, we would not have bought the product since we never heard of this trust firm before. We trusted ICBC because it is the largest bank in China,” said Mr. Zhang.

Both ICBC and China Credit Trust did not immediately respond to requests for comment.

China’s trust industry has experienced explosive growth in recent years, with the amount of outstanding trust assets under management at 12.48 trillion yuan at the end of June, according to the latest data from the China Trustee Association, a government-backed industry group — more than quadruple the amount from four years ago.

A large part of the trust business in China involves extending loans on behalf of banks in a way that doesn’t appear on their balance sheets. Such opacity has led to uncertainty over the extent of the banking system’s exposure to trust products.

China Credit Trust has experienced setbacks before. In January, the trust firm was nearly forced to default on another trust product it issued, also sold by ICBC, that was used to fund a coal mine in northern China’s Shanxi Province. At the last minute, however, an unnamed party stepped in and bailed it out.

“A representative with ICBC Shanghai told me that we should have faith in the bank as the first [China Credit Trust] product it sold managed to avoid default before,” said Shanghai-based investor Grace Wang. “The representative told me that ‘you should believe that ICBC is capable of handling [the repayment] of your principal and interest,’” said Ms. Wang.

Ms. Wang said the ICBC Shanghai branch promised investors that the bank would formally respond to investors next week.

In recent months, several defaults and near-defaults in the financial sector have sent jitters to the market and prompted investors to grow increasingly aware of the potential risks attached to trust products.

According to latest data from the central bank, trust loans declined by 15.8 billion yuan in July, the result of a regulatory crackdown on shadow banking and investors’ risk averseness, analysts said. A slower growth or even a decline in trust lending will make it harder for some firms to roll over loans, analysts said, which means more defaults may come.

That’s especially worrisome given the fact that Credit Suisse estimated in July that some 4.2 trillion yuan of trust loans are scheduled for repayment in the coming nine months.

Mr. Zhang said he was highly skeptical that the trust company would be able to pay investors back even on an extended timeline of 15 months.

“We demand ICBC to pay back our investment. Or we will march to Beijing where the bank is headquartered,” he said.

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